The present invention relates generally to disk drives for storing data. More specifically, the present invention relates to a drive housing for a disk drive that inhibits leakage of fluid into or out of the housing.
Disk drives are widely used in computers and data processing systems for storing information in digital form. These disk drives commonly use one or more rotating magnetic storage disks to store data positioned within a drive housing. Each storage disk typically includes a data storage surface on each side of the storage disk. These storage surfaces are divided into a plurality of narrow, annular, regions of different radii, commonly referred to as xe2x80x9ctracksxe2x80x9d. Typically, an E-block having one or more actuator arms is used to position a data transducer of a transducer assembly proximate each data storage surface of each storage disk. An actuator motor is used to provide a driving force for moving the E-block relative to the storage disks. A connector assembly including a connector housing and a plurality of connector pins is typically used to transfer electrical signals through the drive housing.
The need for increased storage capacity and compact construction of the disk drive has led to the use of disks having increased track density and decreased track pitch, i.e., more tracks per inch. Additionally, the speed at which the storage disks rotate is rapidly increasing. This causes higher turbulence and windage excitation of the actuator arms and the transducer assemblies. As the tracks per inch and disk speed increase, the ability to maintain the data transducer on a target track becomes more difficult. More specifically, with advances in track density and disk speed, it is particularly necessary to reduce positioning error of the data transducer (also known as xe2x80x9ctrack misregistrationxe2x80x9d) proportionally. With these systems, the accurate and stable positioning of the data transducer proximate the appropriate track is critical to the accurate transfer and/or retrieval of information from the rotating storage disks.
An attempt to compensate for the increase in turbulence and windage includes filling the drive housing with gases such as helium or hydrogen. In this design, the drive housing is hermetically sealed in order to maintain the desired gas within the drive housing. Although the premise of hermetically sealing a disk drive in order to reduce track misregistration is sound, maintaining a sufficient seal has historically been problematic. Over time, the gas (such as helium or hydrogen) escapes from within the drive housing, resulting in a decrease in pressure and potential displacement of the desired gas with air, which ultimately can cause track misregistration due to the turbulence and windage.
Preferably, the desired gas is contained within the drive housing so that less than five percent (5%) leaks out over a five-year period. This translates into a leak rate of less than 4.8xc3x9710xe2x88x928 cubic centimeters per second (0.000000048 cc/sec). To accomplish this extremely low leakage level, drive manufacturers face three major challenges. First, the drive housing must be hermetically sealed. Second, the electrical signals must be carried in and out of the disk drive without compromising the seal. Third, the technology to meet the first two challenges must be economically and commercially feasible.
With conventional drive housings, leakages can occur at various locations in the drive housing. For example, conventional drive housings typically include a metal housing base having a base aperture that receives the connector housing of the connector assembly. Further, the connector housing is sealed to the housing base and the individual connector pins are sealed to the connector housing with an insulator or sealing material. Unfortunately, with this design, leakages can occur at the junction between the connector housing and the drive housing, or between the connector pins and the connector housing. Further, the seals can weaken or fail resulting in escaping of the gases from the drive housing.
In light of the above, the need exists to provide a disk drive with a decreased incidence of track misregistration. Additionally, the need exists for a hermetically sealed drive housing that inhibits leakage of a desired fluid maintained within the drive housing for an extended period of time. A further need exists to provide a manner of carrying electrical signals in and out of the drive housing without compromising the hermetic seal of the drive housing. Still another need exists to provide a disk drive that is relatively easy and inexpensive to manufacture.
The present invention is directed to a drive housing for a disk drive which satisfies these needs, and a method for inhibiting leakage of a fluid into or out of a housing chamber of the disk drive. The drive housing typically includes a housing cover wall, a housing base wall, and four side walls that secure the housing base wall to the housing cover wall. As provided herein, one of the housing walls includes a wall aperture. Further, the drive housing also includes at least one connector that carries electrical signals through the drive housing. Each of the connectors can be a connector pin, or alternatively, an edge card connector.
Uniquely, each connector extends through a corresponding wall aperture. For each connector, the drive housing also includes a sealer that seals the connector to the housing wall to inhibit the flow of gas through the housing base. With this design, the connectors are positioned and integrated directly into the drive housing and the need for an additional seal between the drive housing and a connector housing is eliminated. As a consequence, leakage of fluid through the drive housing of the disk drive is significantly reduced.
Preferably, the housing wall has a wall coefficient of thermal expansion, and the sealer has a sealer coefficient of thermal expansion. Importantly, the wall coefficient of thermal expansion is substantially similar to the sealer coefficient of thermal expansion. As a consequence, the potential for leakage is further inhibited.
Additionally, the present invention includes a method for providing a controlled environment for a disk drive. The method includes the steps of providing a drive housing that includes a housing wall having at least one wall aperture, positioning a connector so that the connector extends through the wall aperture, and sealing the connector directly to the housing wall.